"It crossed the churchyard with a sigh,
And said, "Not yet ! in quiet lie."'"

LONGFELLOW.

Thus sang the brooklet, as the pretty stars, like shining gold-fish, sank deeper and deeper into the pale-blue sea of the sky.

" I wish my little friends were here to see the break of day," it added, and its purling ripples seemed to linger near the sleeping pebbles, as if searching for Bunny and his cheerful companions.

"Here we are ! " rang a merry chorus, and down trooped our happy band, with nimble Chip running before.

"Just in time ! " rippled the brooklet softly ; "for I am to show you why the days, nights and seasons visit our valley, and here is a day close at hand.

" First, let me tell you that the earth is a large ball, rounder than the button-balls on the bush that hangs over the water ; rounder than an apple,yes, rounder than the base-ball with which the boys sometimes play in our valley ; and yet it is not perfectly round.

"This great ball rolls over and over in space just like the soap-bubbles which the little girl blew here yesterday."

"Does the earth float about in the air just as the soap-bubbles did?" asked Dick.

"0 no ! " babbled the brook. "The air does not hold the earth in its place ; but land, water and air form this great ball that turns in space, while the sun shines in nearly the same place in the sky both day and night."

That was too much for little Chip, for had he not seen the sun move across the sky every pleasant day for many months? At last the bright creature broke forth. " Then why do we not see the sun at night as well as in the daytime ?"

" I will show you, my cheery friend, if you will help me. We will use this large wind-mill which the boys made here last summer. See it turning very slowly in the morning breeze. The top is rolling towards the sun, and the bottom away from the burning ball which shines high above the horizon.

Now, Chip, I want you to climb to the very top of the wind-mill, face the sun in the east, and swing slowly round with the great wooden wheel. You can then tell us how the sun seems to move."

There it is ! " chirped the cunning creature, as he climbed nimbly to the topmost point of the wind-mill. " The bright sun is just in front of me. 0 see it go ! now it is over my head and shines on my back. Now it is behind me. There it goes out of sight behind the wind-mill. I never saw it travel so fast before. It will be night before I can reach home"; and the little fellow was about to scamper down and away, when he heard a merry laugh below him.

" Why, Chip ! the sun is in just the same place," chirped Redbreast. " Wait a minute, and you will see it again."

" There it comes ! " shouted the chipmonk. "It is rising in front of me once more."

So over and over the great wheel swung, with Chip clinging to its long arm, while the sun seemed to him to rise and set at every turning. First his back and then his legs were towards the flaming ball, as he was rolled into the sunlight, then back into the shade.

" If the wheel were very, very large," chirped the robin, " it would be day on the light side, and night in the shadow."

" Yes ; and morning as he swings into the sun-light, and evening as he sinks into the shadow," added Dick.

The little stream seemed to bubble with joy as it listened to the chatter. Then it told its little friends how the great ball on which we live turns or rotates like the wind-mill ; how it rolls us into darkness every evening, and back to the light every morning, thus causing days and nights in the valley.

" But you must not think that the whole sky above us is dark at night," prattled the stream. " Try to find some shadows on my beach, and I will then tell you about the one cast by the great earth."

"Here is one now, behind this rock," piped Redbreast. "It looks like the long cones hanging on the pine-trees."

" Yes ; and as the earth is much smaller than the sun, its shadow runs to a point far above our heads at midnight," added the brooklet. " Night is a long, cone-shaped shadow cast by the earth far into space.

" Once in a while, the moon sails into this shadow, and its round face is no longer lighted by the sun. Then it sails out again, and the eclipse is over.

" So round and round goes our valley on the great earth, swinging us into the light of day, and then into the shadow of night."

"But why do we not fall from the earth at night when our heads hang down ? " queried Bunny. " I should think that all the water would spill out of our pond, too."

The pretty stream was puzzled for a moment. How could it explain to the rabbit that its head did not hang down ? But soon its silvery voice rang out, " There is a small dark stone at the foot of the ledge, near the sweet acorn tree. I saw it one day as I trickled down the steep slope. If you will bring it to me, Bunny, I will show you why we do not fall from the earth at night."

"Here it is ! " called out the rabbit from the ledge. " There is a small nail clinging to it."

"What a queer rock ! " cried Dick. " It holds the nail so firmly that I cannot shake it off."

" It is a piece of iron ore that acts like a magnet," began the brook. "It is called a `load-stone,' and draws to itself small pieces of steel and iron. Now if you will stand the little nail on its flat end, and turn the stone round and round, you will see that the nail will always point to the centre of the magnet. Over or under, right or left, the nail still stands upright, away from the loadstone.

" The earth acts like a great magnet also, and draws towards itself not only iron and steel, but also every other substance. Whether our heads or our feet are nearer the sun, we are drawn towards a point near the centre of the earth.

Up' is not towards the sun, or any one place in the sky. Up means away from the centre of the earth, and down means towards the centre.

" At night, the trees still stand upright because they point away from the earth, even though the trees half-way round the great ball grow in the opposite direction.

" And when we walk at midnight, our heads do not hang down, for down is towards the earth."

" But why does not the sun rise in the same place day after day ? " piped robin. " Sometimes we see it come over the hill, then over the narrow gully, and even over the treetops when the snow is on the ground."

"And it does not always set in the same place," squeaked Chip.

" Nor rise so high in the sky in winter," added Bunny. " In summer the noon shadows are very short, and the bright ball is nearly overhead."

"I will tell you why it rises farther north, and travels in a higher arch in summer time," began the brook.

" Last night we saw a bright star just in line with the top of our tallest pine. Can you recall its name ? "

" Pole star ! " cried Chip.

" North star ! " sang Redbreast.

" Both are right. It has several names, and is the most useful to us of all the stars. It is nearly due north, and as it does not rise and set, it can be seen every clear evening. If it were night now, we could see it shining there just above the treetop.

"A point on earth nearly under that star is called the `north pole.' If we could run a line from the north star, through the centre of the earth to the opposite side, it would come out near a point called the ` south pole.'

"Let us call the place on this plump round apple, where the stem grows, the north pole, and the blossom end, the south pole. Just midway between the poles, Dick may scratch a line round the apple. The north pole is in the centre of the northern half, and the south pole in the centre of the southern.

" That dark spot on the apple, more than one-third of the distance from the equator towards the north pole, shows you where our valley is on the earth.

"Now Robin may peck into the blossom end,  the south pole,  and hold the apple on his bill so that the stem endthe north pole  will point over the top of the pine towards the north star.

Chip may sit on that rock about a foot behind Robin, just on a level with the apple, and watch closely. What part of the apple can you see, little chipmonk ? "

" There is the south pole, but I cannot see the north," said Chip.

"If your head were the sun, which half of the apple would be lighter ? " asked the brook.

" The southern," was the quick reply ; "for I can see more of it."

" Now Robin may move slowly round the little squirrel, towards the west, still keeping the apple-stem pointed over the pine, and Chip may tell us when he can see the north pole," bubbled the stream.

Hold ! there it is ! " came the shrill chirp, when Redbreast had hopped one-quarter way round. " Now I can see both poles. If my head were the sun, it would light north and south alike."

"Look again, Chip, while Robin moves round another quarter. Now what parts can you see ? asked the brook.

" The south pole is not in sight ; but I can see far beyond the north pole, and more than half the northern part of the apple."

" Hop round a little farther, Redbreast, and Chip will call out when he can see both poles again," rippled the brooklet.

" There they are ! " sang the bright-eyed squirrel, as the robin reached the third quarter.

Then the willing little bird moved along to the starting-point, and again the north pole sank out of sight, still pointing over the tall pines.

" We will now speak of the apple as if it were the earth, and we will call the line which Dick scratched upon it 'the equator,' " said the brook.

Chip may tell us whether the part of the apple nearest him is north or south of the equator."

" South," was the prompt answer.

"If your head were the hot sun, would the north or south part of the earth receive more heat ? " bubbled the stream.

" It would be much warmer south of the equator than north," said Chip.

" Yes," added the brook ; " in the southern half warm summer is just beginning, while on the northern side cold winter is setting in.

"Now Robin may hop round once more, till Chip can see both poles again. Ah ! keep the north pole over the old pine, little Redbreast. There ! on which side of the equator do the warmest rays shine now ? "

" Both sides of the equator are heated alike," said Chip. " The sun is just over the middle line."

" Then which half of the earth is warmer, Bunny,  the northern or southern?" came the query, and a roguish ripple rolled in among the smooth pebbles.

" One side must be just as warm as the other," said the rabbit, " for the sun shines on both alike."

"That cannot be," cried Dick. "It has just been summer south of the equator, and winter north. I think it would still be warmer in the south."

" You are right, Dick. I did not think of that," added Bunny. It is like morning and evening. When the sun is setting, it is leaving a surface that has been warmed all day. When it is rising, it must first heat the earth before its warmth is given off into the air. Thus we find the dawn much cooler than the eve, although the sun's rays are just as slanting.

" Spring is the dawn of the seasons, and autumn the eve ; winter is the night, and summer the mid-day."

"Well said, Bunny," babbled the waves ; "but let us look again to Robin's earth. When it reaches this point, and the sun shines above the equator, two seasons begin, and two end. In the north, cold winter goes out, and  "

Warm spring comes in ! " sang the merry voices.

"But how is it south of the equator, my little friends ? " asked the brooklet.

"Autumn must follow summer there, for it does here," said Redbreast, as well as he could with the apple on his bill.

"That is true, pretty bird," sang the stream. "And now you may move round another quarter."

" 0, I know that it must be summer in the north, for I can see only a little of the part south of the equator," called out Chip. Then he added, " It must be winter in the southern half, because the surface is turned so far away from me. The lighted place in the south is so narrow that the daylight cannot last so long as it does in the north."

"That must be the reason why our days are so much longer in summer; and the longer the day, the warmer it must be," said thoughtful Dick. " But there goes Robin again."

"Hold! " cried Chip. " The sun is over the equator again, and shines on both sides alike. It must be spring on one side, and autumn on the other."

" It is autumn in the north," said Bunny, " for summer is just over. And it must be spring in the south."

" Here we are back to our winter in the north ! " shouted Chip, as the robin hopped along to the starting-point, and dropped the apple from its tired bill. "It has taken four whole seasons for the earth to move round the sun. How slowly it must go ! "

" 0 no ! " rippled the brook. "It moves very rapidly. Our valley is about a quarter of a mile in length. Listen, while I count as fast as I can,  one, two, three, four, five, six,  and the earth has moved a hundred times the length of our valley while I was counting.

" Take this apple, please, Dick, and drop it from the bough that hangs over the water. Watch it ! Let it go ! "

" 0, how swift ! " chirped the robin.

" The apple fell only about sixteen feet," said the brook ; " but while it was in the air, the earth whizzed along more than sixteen miles sixty-four times the length of our valley  on its way around the sun. And every time it revolves, or goes round, we have our four seasons.

"As we. look at the sun day after day for a year, it seems to rise higher and higher in the sky at noon for a while, and then to move in a lower and lower path. When it reaches its highest arch, our northern summer begins, while its lowest path marks the beginning of our win-ter.

"Its middle arch, as it seems to travel higher and higher, opens the spring, while the same line, on its southward journey, brings in the autumn.

" Now, my little companions, you know why the days, nights and seasons visit our home, and to-morrow I will tell you how they help to cover our valley with life."